Adaptive data slicer with two peak detectors and averaging means to obtain the optimal threshold

摘要

An adaptive data slicer (40) which functions to adapt to changes in the properties of a signal input thereto by producing a near optimal slicing threshold in accordance with the input signal for use in a decision circuit. The slicing level is considered optimal when its use in the decision circuit minimizes the bit error probability. The data slicer utilizes two peak detectors, a maximum peak detector (42) for detecting the highest levels of the input signal and a minimum peak detector (44) for detecting the lowest levels of the input signal. The peak detector outputs are averaged (58) to obtain the optimal slicing threshold (VTH-OPT).This threshold is then used to determine the received digital data. The data slicer (40) incorporates adaptation circuitry (48,50,52) which is operative to dynamically adjust the discharge rate of the holding circuits in both maximum and minimum peak detectors. A discharche processor (48) functions to generate a control signal used to control the discharge rate, i.e. the current sources used for both peak detectors. The maximum peak detector is discharged to ground (50) while the minimum peak detector is discharged to the supply voltage (52). The control signal is generated in accordance with a particular function chosen to exhibit desired discharge properties wherein the instantaneous values of the two peak detector outputs (VMAX,VMIN) comprise the input to the function.